There are a number of industrial control, communication and information systems on the market which involve compact solid state audible signalling devices which provide distinctly different, selectable and programmable compelling alarm sounds which are produced to fit particular noise and ambient conditions in signalling requirements. A family of these devices is sold by the assignee hereof under the trademark "CYBERBLAST.RTM.". These devices can produce a plurality of distinctly different, selectable and programmable compelling alarm sounds which can be produced to fit particular ambient noise conditions and signalling requirements as encountered in the field. However, in some situations, such as the Three Mile Island nuclear accident, someone upon hearing an alarm became confused and took the wrong corrective action. Such a situation could possibly have been avoided had the alarm been verbal, such as giving express directions as to the corrective action to be taken e.g. "open safety valve one and close dump valve two".
In the past there have been a number of computer generated speech synthesizers such as the IBM 770 series audio response units which are capable of being connected to IBM system 360 computers via multiplexer channels to a signalling network. However, such units were extremely expensive, but with the advent of low cost speech synthesis processor units (VSP), verbal communication with a microprocessor computer based system has become readily available. There are a number of commercially available units in which programmable alarms are utilized such as produced by Butler National Corporation, Federal Sound and Signal Corporation, Telesensory Systems, Inc. and Data Voice Corporation of Chicago, Ill. Such units have been incorporated in computers and machines and in many industrial applications where a verbal output is preferred for warnings, alarms and instructions for corrective action.
The object of the present invention is to provide an improved industrial control communication and information system in which a voice synthesizer is utilized to provide verbal warnings, alarms and instruction for corrective action to be taken.
Another object of the invention is to provide an improved interface system which uses the input alarm condition switch closure to switch power onto the internal logic and other electronic circuits in the system and also protects the internal logic from harsh external electrical conditions such as transients and the like, and conditions the input signals to eliminate false inputs and the effects of switch bounce.
In a preferred embodiment of the invention switch closures denoting an alarm condition for which a voice alarm, warning or verbal instruction is to be produced, are coupled through an interface circuit which includes an optical couple for each signalling system to isolate the input switch closures and other harsh external electrical condition transients from affecting the internal logic conditions. The signals to the optical couples are conditioned to eliminate false inputs and switch bounce. Each such switch closure operates its own optical couple to provide an input signal of an alarm condition. These input signals are polled or scanned by a central processing unit (CPU) in which all functions are memory mapped, that is, each device resides at a specific memory address which is decoded as a memory location. The central processing unit (CPU) performs all major system control functions such as decoding of the inputs, establishment of an input priority, the look-up of the data necessary to speak a selected phrase, control of commands to the voice synthesis processor (VSP) as required for its operation, management of the voice data flow for use by the VSP and polls the input state condition for change, such as discontinuing the speaking of an old phrase and initiating the speaking of a new phrase (e.g. an alarm of a higher priority). A bi-directional data bus (of 8 bits) is coupled between the CPU, the input buffer circuits, and the voice synthesis processor. In addition, an erasable programmable read only memory (ROM) is utilized for storing instructions used by the CPU in execution of the system function. In addition, the memory stores the program instruction sequence, the coded data for the speech synthesis and the look-up tables used by the CPU program to identify which phrase has been selected for voice synthesis, to locate the data in memory for the processing of a particular word, the amount of data required for that word and the length of the pause following the word. Each eight bit byte within the read only memories (ROM's) is mapped to a distinct memory address and can be accessed by the memory address bus in conjunction with the appropriate enabling signal from the decode logic.
The voice synthesis processor (VSP) receives voice data from the data bus byte by byte sequentially. When decoded with the appropriate command (also from the data bus), the VSP will interpret the data to determine the necessary pitch, amplitude and filtering characteristics required to reconstruct a string of digital codes corresponding to the audio waveform of the speech from which the data was initially derived. This string is then subjected to a digital to analog conversion, also within the VSP chip. The result is a stepped waveform analogous to the audio waveform of the recorded speech. This waveform is available at the output of the VSP. The VSP is mapped in the system at a specific memory location and is addressed by the decode logic as though it were a single memory word.
The decode and interface and logic section decodes the states of the address bus, and in conjunction with the control lines selects the source or destination of data on the data bus and provides the necessary strobe signals to implement the writing of data into the appropriate receiving device. All of these signals originate with the CPU which is the ultimate source of all synchronization and direction of data flow.